Coating compositions for photolithography

ABSTRACT

Underlying coating compositions are provided that comprise one or more resins comprising one or more modified imide groups. These coating compositions are particularly useful as antireflective layers for an overcoated photoresist layer. Preferred systems can be thermally treated to increase hydrophilicity of the composition coating layer to inhibit undesired intermixing with an overcoated organic composition layer, while rendering the composition coating layer removable with aqueous alkaline photoresist developer.

This invention relates generally to the field of manufacture ofelectronic devices. In particular, this invention relates to themanufacture of integrated circuit devices containing through use of newcompositions and processes.

The present invention involves compositions (including antireflectivecoating compositions or “ARCs”) that can reduce reflection of exposingradiation from a substrate back into an overcoated photoresist layerand/or function as a planarizing or via-fill layer. More particularly,the invention relates to organic coating compositions, particularlyantireflective coating compositions, that comprise one or more resinsthat comprise modified imide groups such as modified glutarimide and/ormaleimide groups

Photoresists are photosensitive films used for the transfer of images toa substrate. A coating layer of a photoresist is formed on a substrateand the photoresist layer is then exposed through a photomask to asource of activating radiation. The photomask has areas that are opaqueto activating radiation and other areas that are transparent toactivating radiation. Exposure to activating radiation provides aphotoinduced or chemical transformation of the photoresist coating tothereby transfer the pattern of the photomask to the photoresist-coatedsubstrate. Following exposure, the photoresist is developed to provide arelief image that permits selective processing of a substrate.

A major use of photoresists is in semiconductor manufacture where anobject is to convert a highly polished semiconductor slice, such assilicon or gallium arsenide, into a complex matrix of electronconducting paths, preferably of micron or submicron geometry, thatperform circuit functions. Proper photoresist processing is a key toattaining this object. While there is a strong interdependency among thevarious photoresist processing steps, exposure is believed to be one ofthe most important steps in attaining high resolution photoresistimages.

Reflection of activating radiation used to expose a photoresist oftenposes limits on resolution of the image patterned in the photoresistlayer. Reflection of radiation from the substrate/photoresist interfacecan produce spatial variations in the radiation intensity in thephotoresist, resulting in non-uniform photoresist linewidth upondevelopment. Radiation also can scatter from the substrate/photoresistinterface into regions of the photoresist where exposure is nonintended, again resulting in linewidth variations. The amount ofscattering and reflection will typically vary from region to region,resulting in further linewidth non-uniformity. Variations in substratetopography also can give rise to resolution-limiting problems.

One approach used to reduce the problem of reflected radiation has beenthe use of a radiation absorbing layer interposed between the substratesurface and the photoresist coating layer. See U.S. Patent Publication2005/0112494. Electronic device manufacturers continually seek increasedresolution of a photoresist image patterned over antireflective coatinglayers and in turn demand ever-increasing performance from anantireflective composition.

It thus would be desirable to have new antireflective compositions foruse with an overcoated photoresist.

We now provide new organic coating compositions that comprise acomponent that can be thermally treated to increase hydrophilicity, butwithout significant molecular gains (e.g. without extensivecrosslinking) of components of the coating composition layer.

Thus, a coating composition of the invention can be formulated in one ormore organic solvents such as used to formulate a photoresistcomposition; the coating composition applied to a substrate; the appliedcoating layer thermally treated to increase hydrophilicity of the layer;and a photoresist composition layer applied above the thermally treatedlayer. The increased hydrophilicity of the underlayer inhibitsintermixing of that layer the overcoated resist layer. The photoresistlayer then may be exposed to patterned activating radiation anddeveloped such as with an aqueous alkaline developer composition. Inpreferred aspects, use of an aqueous alkaline developer composition canremove regions of the underlying coating composition that lie beneathdeveloped photoresist regions.

In preferred aspects, the organic coating composition comprises acomponent that include one or more imide groups, such as one or moreresins that comprise repeat units that contain imide groups. Preferredresins include copolymers, terpolymers, tetrapolymers or other higherorder polymer where the resin comprises one or more distinct repeatunits in addition to an imide moiety.

In particularly preferred aspects, the organic coating compositioncomprises a component that includes one or more modified imide groups,such as one or more resins that comprise repeat units that containsmodified imide groups. Imide groups that have N-substitution with athermally reactive (e.g. cleavable) moiety are especially preferredmodified imide groups.

In particular, an N-substituted modified imide functionality can providea deblocked imide group upon thermal treatment, i.e. thermal treatmentcan result in cleavage of the N-substituted moiety to provide the morehydrophilic unsubstituted imide (—N(C═O)₂H) group.

Alternatively, an N-substituted imide functionality can provide ahydrophilic group while retaining N-substitution of the imide group.Thus, for instance, an N-substituted imide group of the general formula—N(C═O)₂R can be thermally treated where the R group in that formulareacts to provide a more hydrophilic group of the general formula—N(C═O)₂R¹X where X is a hydrophilic group such as a carboxyl (COOH) orsulfonic acid moiety and R¹ is a linker such as a C₁₋₁₆alkylene e.g.—CH₂— or —CH₂CH₂—.

Imide groups may be modified with a variety of groups, such as estergroups (particularly tertiary esters that can be more thermallyreactive) and acetal groups.

In preferred aspects of the invention, thermal treatment of theunderlying coating composition does not induce significant molecularweight increases of composition component(s). For instance, one or morecomposition component components do not typically increase molecularweight more than 10, 20, 30, 40, 50 or 80 percent as a result of thethermal treatment. Thus, a crosslinking reaction (or at leastsignificant crosslinking) is not a typical reaction induced by thethermal treatment in such preferred embodiments.

In such aspects of the invention, the underlying coating compositiondoes not need to contain an additional crosslinker component (such as anamine material) as has been employed in prior underlying antireflectivecoating compositions. Thus, the underlying coating composition may be atleast substantially, essentially or completely free of an addedcrosslinker component such as an amine material. An underlying coatingcomposition will be at least substantially free of crosslinker if lessthan 5, 4, 3, 2 or 1 weight percent solids (all components exceptsolvent carrier) are other than a crosslinker such as an amine-basedmaterial (e.g. benzoguanamine or melamine material).

An underlying coating composition of the invention optionally maycomprise acid or an acid generator (e.g. photoacid-generator or thermalacid generator) to facilitate reaction during the thermal treatmentstep, e.g. to enable de-blocking of an N-substituted imide group atcomparatively lower temperatures and/or shorter heating cycle times.

Preferred underlying compositions also may comprise one or morechromophore groups to thereby enhance functionality as antireflectivelayers for an overcoated photoresist layer. Preferred chromophore groupsare aromatic groups such as phenyl groups for use with an overcoatedphotoresists imaged at 193 nm and anthracene and naphthylene groups foruse with overcoated photoresists imaged at 248 nm.

In particular aspects, the underlying coating composition may compriseone or more resins that comprise repeat units that contain chromophoregroups such as phenyl, anthracene and/or naphthyl. Groups that canprovide enhanced hydrophilicity upon thermal treatment (such asN-substituted imide groups) can be present on the same component (e.g.resin) as such chromophore groups, or chromophore groups and thermallyreactive groups such as N-substituted imide groups can be present onseparate composition components such as separate (i.e. not covalentlylinked) resins.

One or more resins present in underlying coating compositions of theinvention may comprise a variety of other repeat units, such as repeatunits that comprise one or more of anhydride (e.g. maleic anhydride oritaconic anhydride), lactone (e.g. butyrolactone such asγ-butyrolactone), carbon alicyclic (e.g. adamantyl, norbornyl), acrylategroups, cyano groups, and hydroxyl groups, among others.

The invention also includes coated substrates, which may comprise asubstrate having thereon (1) an organic coating composition as disclosedherein; and (2) a further composition layer above that organiccomposition. The overlying further composition may be e.g. a layer thatcomprises one or more organic component such as a photoresistcomposition, a hardmask composition, a lift-off layer, or othercompositions. The substrate may be e.g. a microelectronic wafersubstrate. Suitably, an organic or inorganic dielectric layer may beinterposed between the substrate and the organic composition.

In a further aspect, the invention also includes a polymer whichcomprises repeat units that contain modified imide groups, such asmodified maleimide or glutarimide groups, as disclosed herein.

The invention also include a such polymers that comprise repeat unitsthat contain modified imide groups, wherein the polymer is solvated (atleast significantly in solution) at room temperature (24° C.) in one ormore organic solvents used to formulate photoresist compositions such asethyl lactate and/or propylene glycol methyl ether acetate.

A variety of photoresists may be used in combination (i.e. overcoated)with a coating composition of the invention. Preferred photoresists foruse with the underlying coating compositions of the invention arechemically-amplified resists, especially positive-acting photoresiststhat contain one or more photoacid generator compounds and a resincomponent that contains units that undergo a deblocking or cleavagereaction in the presence of photogenerated acid, such asphotoacid-labile ester, acetal, ketal or ether units. Negative-actingphotoresists also can be employed with coating compositions of theinvention, such as resists that crosslink (i.e. cure or harden) uponexposure to activating radiation. Preferred photoresists for use with acoating composition of the invention may be imaged with relativelyshort-wavelength radiation, e.g. radiation having a wavelength of lessthan 300 nm or less than 260 nm such as about 248 nm, or radiationhaving a wavelength of less than about 200 nm, such as 193 nm.

As discussed above, in addition to or in place of a photoresistcomposition, other composition may be applied above a coatingcomposition of the invention. For instance, a hardmask composition, alift-off composition layer, a passivation layer, or other materials maybe applied above a coating composition of the invention. Suchovercoating layer(s) suitable comprise one or more organic components(e.g. organic resin), but inorganic layers also may be applied above acoating composition of the invention. Additionally, such overcoatinglayers may be suitably photoimageable (such as a photoresist) ornon-photoimageable.

Other aspects of the invention are disclosed infra.

FIGS. 1A, 1B and 1C show results of Example 4, which follows.

COATING COMPOSITIONS

As discussed above, we now provide new coating compositions that areadvantageously used with an overcoated photoresist composition layer.

Particularly preferred compositions of the invention comprise one ormore resins that comprise repeat units with imide moieties. We havefound that use of modified imide groups (e.g. N-substituted imide groupssuch as groups of the formula —C(═O)NRC(═O)— where N is other thanhydrogen particularly an organic group with one or more hetero (N, O orS) atoms) can render resins soluble in common photoresist and edge beadremoval solvents (e.g., ethyl lactate, propylene glycol methyl etheracetate (PGMEA), cyclohexanone) and can be spin coated to give thinfilms with good planarity. Upon a short thermal treatment, with orwithout the presence of acid, preferred imide-modifying moieties canundergo a de-blocking reaction that renders the imide-resinscomparatively insoluble to the solvent(s) that the coating compositionwere originally cast from. Particularly preferred thermally treatedimide polymers of the invention are base soluble and can be readilyremoved with standard aqueous alkaline developer, such as a 0.26Naqueous tetramethyl ammonium hydroxide developer.

Thus, particularly preferred coating compositions of the invention canbe formulated in photoresist solvent(s) (i.e. the composition componentsare soluble in such solvent(s)).

As discussed above, in preferred coating compositions of the invention,thermal treatment of a coating layer of the composition can render thecoating layer comparatively insoluble in photoresist solvents and thus aphotoresist layer can be coated thereon with minimal intermixing of thelayers.

Also, as discussed above, in preferred coating composition thermaltreated composition layers can be removed with aqueous alkalinedeveloper composition. Thus, in preferred aspects, the underlayingcoating composition is rendered sufficiently hydrophilic after thethermal treatment so that the coating layer has reasonable solubility inaqueous alkaline developer used to develop the overcoated resist layer,thereby enabling development of both the resist and underlyingcomposition layer in a single development step.

The following exemplary Scheme 1 depicts a suitable system of theinvention, where a resin containing the depicted dimethylglutarimidegroup is N-substituted with a methylene t-butyl ester group. OtherN-substitution can be readily made. The N-substitution renders the resinmore hydrophobic and thus soluble in organic solvents typically used forphotoresist formulation such as ethyl lactate and/or propylene glycolmethyl ether acetate. An underlying coating composition then can bethermally treated to produce a more hydrophilic group such as thecarboxy moiety depicted in the Scheme 1 below. That increasedhydrophilicity will inhibit intermixing of the coating composition withan overcoated photoresist composition layer, but render the layersoluble in an aqueous alkaline developer.

Scheme 2 below shows a further imide modification in accordance with theinvention where an imide (polyglutarimide shown) is reacted withdi-tert-butyl dicarbonate under basic conditions to provide thecarbamate group depicted above. The carbamate polymer can be soluble intypical photoresist solvents such as ethyl lactate and/or propyleneglycol methyl ether acetate. An underlying coating composition thatcontains the polymer then can be thermally treated to produce a morehydrophilic group such as the imide moiety depicted in the below Scheme2. That increased hydrophilicity will inhibit intermixing of the coatingcomposition with an overcoated photoresist composition layer, but renderthe layer soluble in an aqueous alkaline developer.

Preferred underlying composition layers of the invention can exhibitnotable planarization properties including via and gap fill withoutvoids.

Preferred underlying coating composition layers of the invention alsocan exhibit high modulus, high glass transition temperature (e.g. >150°C.), high thermal stability (e.g., >300° C.) and/or low outgassing ofcomposition components.

Preferred underlying coating compositions of the invention also canexhibit low defect counts of a substrate (e.g. microelectronic wafer)processed with the coating composition.

Preferred underlying coating compositions of the invention also canexhibit large selectivity differential between oxide and reductive etch.

Specifically preferred underlying coating compositions of the inventioninclude resins that contain glutarimide particularly dimethylglutarimidegroups and/or polymerized maleimide groups. Preferred resins includecopolymers, terpolymers, tetrapolymers or other higher order polymerwhere the resin comprises one or more distinct repeat units in additionto an imide moiety. Thus, for instance, in one preferred system, acoating composition comprises a polymer comprises dimethylglutarimideand/or polymerized maleimide repeat units in addition to acrylate groupssuch as methyl methacrylate and/or methacrylic acid units.

For instance, in certain aspects, suitable resins may comprise units ofthe following formulae (I), (II), (III) and (IV):

wherein in those Formulae (I), (II), (III) and (IV):

each X is independently hydrogen or C₁₋₆alkyl such as methyl andpreferably X moieties of glutarimide moieties are methyl;

R and R¹ are each independently hydrogen or a non-hydrogen substituentsuch as a chromophore group (e.g. an aromatic group such a s phenyl,naphthyl or anthracene), C₁₋₂₀alkyl, ester such as a group of theformula —(CH₂)_(n)C(═O)OY where n is an integer of 0 to 15 and Y is aC₁₋₂₀ alkyl group and preferably Y is a group such as tert-butyl toprovide a tertiary ester, or other groups such as a chromophore group(e.g. an aromatic group such a s phenyl, naphthyl or anthracene), and atleast one of R and R¹ is other than hydrogen and preferably at least oneof R and R¹ is a thermally reactive group such as ester or acetal thatcan undergo reaction during thermal treatment of a coating layercontaining the resin to provide a more hydrophilic group; and

R² is hydrogen or a non-hydrogen substituent such as C₁₋₂₀alkyl.

In certain preferred resins, a resin will have at least one group ofFormulae (I) or (II) above where at least of R and R¹ is other thanhydrogen and preferably is a thermally reactive group such as ester oracetal. Suitably, a resin will have from about 4 to about 80 or 90 ormore weight percent of units of Formulae (I) and (II), based on totalunits of the polymer. A resin may suitably not contain groups ofFormulae (III) and/or ((IV), although good results have been obtainedwith resins having such groups.

As mentioned above, preferred underlying coating compositions also maycontain one or more resins that contain polymerized maleimide such asrepeat units that comprise a structure of the following formula (V):

where in that formula (V) R is hydrogen or a non-hydrogen substituentsuch as C₁₋₂₀alkyl, ester such as a group of the formula—(CH₂)_(n)C(═O)OY where n is an integer of 0 to 15 and Y is a C₁₋₂₀alkyl group and preferably Y is a group such as tert-butyl to provide atertiary ester, and at least one of R and R¹ is other than hydrogen andpreferably the resin comprises maleimide groups of the above formulaewhere R is a non-hydrogen substituent particularly a thermally reactivegroup such as ester or acetal that can undergo reaction during thermaltreatment of a coating layer containing the resin to provide a morehydrophilic group. In the formula (v), the wavy lines indicates resinbackbone linkages.

As discussed above, generally preferred are resins that compriseadditional repeat units distinct from repeat units that contain malemidegroups.

Coating compositions of the invention, particularly for reflectioncontrol applications, also may contain additional dye compounds thatabsorb radiation used to expose an overcoated photoresist layer. Otheroptional additives include surface leveling agents, for example, theleveling agent available under the tradename Silwet 7604 from GeneralElectric, or the surfactant FC 171 or FC 431 available from the 3MCompany.

Resins useful in underlying coating compositions of the invention can bereadily synthesized by known procedures, such as polymerization (e.g. inthe presence of a radical initiator) of one or more acrylate monomerssuch as e.g. maleimide, glutarimide, styrene, t-butylacrylate,t-butylmethacrylate, methylmethacrylate, butylmethacrylatemethylanthracene methacrylate or other anthracene acrylateand the like. Other monomers including anhydrides such as maleicanhydride can be co-polymerized with acrylate monomers. For use inantireflective compositions, one or more co-polymerized monomers cancontain suitable chromophore groups, such as anthracene for use inantireflective coating compositions utilized with an overcoatedphotoresist imaged with 248 nm radiation, or phenyl for use in anantireflective coating composition imaged with 193 nm radiation. Seealso the examples which follow for suitable syntheses of resins usefulin coating compositions of the invention. Suitable polyglutarimidesyntheses are also disclosed in U.S. Pat. Nos. 4,246,374 and 5,004,777.

Thermal reactive groups may be incorporated into a resin by a variety ofapproaches including grafting such groups onto a formed resin asdiscussed above with respect to the Scheme, or including such groups ina monomer or oligomer that is polymerized with other materials to form aresin. For example, thermally-reactive esters and acetal moieties may besuitably grafted onto the nitrogen of imide group of a formed resin. Forinstance, an ester grafted onto a imide nitrogen group is a preferredthermally reactive group (upon thermal treatment, de-esterification toprovide aqueous alkaline developer-solublizing carboxy group, or theester group cleaves to provide the aqueous alkalinedeveloper-solublizing unsubstituted imide group). Such esters may beprovided e.g. by reaction of a haloacetate compound (e.g. tert-butylchloroacetate or t-butyl bromoacetate) with a imide nitrogen group.

Acetal groups also are preferred thermally-reactive groups; for examplea vinyl ether compound may be grafted onto an imide nitrogen to providea thermally reactive acetal group. Suitable vinyl ether reagents toprovide a thermally reactive acetal group include compounds having atleast one —(CH═CH)—O— group such as ethylvinyl ether and the like.

Preferred thermally-reactive esters include the above-discussed t-butylesters as well as other tertiary esters such as dimethyl benzyl i.e.—C(CH₃)₂C₆H₅. Tertiary esters (i.e. groups of the formula —C(═O)OCRR¹R²where R, R¹ and R² are each non-hydrogen substituents) can be morethermally reactive and thus undergo reaction at lower temperaturesand/or shorter thermal treatment times. Nevertheless, other esters alsomay be employed as a benzyl esters and secondary esters such as asec-butyl ester or an iso-propyl ester.

In certain aspects, preferred underlying coating compositions of theinvention may comprise one or more components that comprise anhydrideand hydroxyl moieties. In such preferred compositions, anhydride andhydroxyl moieties may be present together on a single compositioncomponent such as a resin, e.g. by copolymerizing monomers that containhydroxyl groups with anhydride monomers. Alternatively, anhydride andhydroxyl moieties may be present together on a distinct compositioncomponent such as distinct resins, e.g. where one resin comprisesanhydride groups and a distinct resin comprises hydroxyl groups.

As discussed above, for antireflective applications, suitably one ormore of the compounds reacted to form the resin comprise a moiety thatcan function as a chromophore to absorb radiation employed to expose anovercoated photoresist coating layer. Additionally, a chromophore group(such as an aromatic e.g. phenyl, naphthyl or anthracene) may be graftedonto an imide nitrogen.

For example, a phenyl compound such as styrene or a phenyl acrylate(e.g. benzyl acrylate or benzyl methacrylate) may be polymerized withother monomers to provide a resin particularly useful in anantireflective composition employed with a photoresist imaged at sub-200nm wavelengths such as 193 nm. Similarly, resins to be used incompositions with an overcoated photoresist imaged at sub-300 nmwavelengths or sub-200 nm wavelengths such as 248 nm or 193 nm, anaphthyl compound may be polymerized, such as a naphthyl compoundcontaining one or two or more carboxyl substituents e.g. dialkylparticularly di-C₁₋₆alkyl naphthalenedicarboxylate. Reactive anthracenecompounds also are preferred, e.g. an anthracene compound having one ormore carboxy or ester groups, such as one or more methyl ester or ethylester groups.

For deep UV applications (i.e. the overcoated resist is imaged with deepUV radiation), a polymer of an antireflective composition preferablywill absorb reflections in the deep UV range (typically from about 100to 300 nm). Thus, the polymer preferably contains units that are deep UVchromophores, i.e. units that absorb deep UV radiation. Highlyconjugated moieties are generally suitable chromophores. Aromaticgroups, particularly polycyclic hydrocarbon or heterocyclic units, aretypically preferred deep UV chromophore, e.g. groups having from two tothree to four fused or separate rings with 3 to 8 members in each ringand zero to three N, O or S atoms per ring. Such chromophores includeoptionally substituted phenanthryl, optionally substituted anthracyl,optionally substituted acridine, optionally substituted naphthyl,optionally substituted quinolinyl and ring-substituted quinolinyls suchas hydroxyquinolinyl groups. Optionally substituted anthracenyl groupsare particularly preferred for 248 nm imaging of an overcoated resist.Preferred antireflective composition resins have pendant anthracenegroups. Preferred resins include those of Formula I as disclosed on page4 of European Published Application 813114A2 of the Shipley Company.

Another preferred resin binder comprises optionally substitutedquinolinyl groups or a quinolinyl derivative that has one or more N, Oor S ring atoms such as a hydroxyquinolinyl. The polymer may containother units such as carboxy and/or alkyl ester units pendant from thepolymer backbone. A particularly preferred antireflective compositionresin in an acrylic containing such units, such as resins of formula IIdisclosed on pages 4-5 of European Published Application 813114A2 of theShipley Company.

As discussed above, for imaging at 193 nm, the antireflectivecomposition preferably may contain a resin that has phenyl chromophoreunits. For instance, one suitable antireflective resin for use withphotoresists imaged at 193 nm is a terpolymer consisting of polymerizedunits of styrene, maleic anhydride, and 2-hydroxyethyl methacrylate.

Preferably resins of underlying coating compositions of the inventionwill have a weight average molecular weight (Mw) of about 1,000 to about10,000,000 daltons, more typically about 5,000 to about 1,000,000daltons, and a number average molecular weight (Mn) of about 500 toabout 1,000,000 daltons. In certain aspects, preferred resins ofunderlying coating compositions may have a weight average molecularweight of about 2,000 to 100,000, more typically from about 5,000 or10,000 to 50,0000. Molecular weights (either Mw or Mn) of the polymersof the invention are suitably determined by gel permeationchromatography.

While coating composition resins having absorbing chromophores aregenerally preferred, antireflective compositions of the invention maycomprise other resins either as a co-resin or as the sole resin bindercomponent. For example, phenolics, e.g. poly(vinylphenols) and novolaks,may be employed. Such resins are disclosed in the incorporated EuropeanApplication EP 542008 of the Shipley Company. Other resins describedbelow as photoresist resin binders also could be employed in resinbinder components of antireflective compositions of the invention.

The concentration of such a resin component of the coating compositionsof the invention may vary within relatively broad ranges, and in generalthe resin binder is employed in a concentration of from about 50 to 95weight percent of the total of the dry components of the coatingcomposition, more typically from about 60 to 90 weight percent of thetotal dry components (all components except solvent carrier).

Acid or Acid Generator Compound (Optional Component)

Coating compositions of the invention may comprise additional optionalcomponents. Thus, for example, a coating composition may suitablycomprise an added acid source such as an acid or acid generator compoundparticularly a thermal acid generator compound. The added acid canfacilitate the thermally promoted reaction during the thermal treatmentstep, thereby enabling the reaction to increase hydrophilicity of theunderlying composition layer to proceed at lower temperatures andshorter times.

However, as discussed above, in preferred aspects, underlying coatingcompositions of the invention may be formulated without such an addedacid or acid generator compound(s). Such compositions free or at leastessentially free of any added acid or acid generator compounds mayprovide performance benefits, including enhanced shelf life and reduceddefects. As referred to herein a composition that is essentially free ofadded acid or acid generator compounds has less than 3, 2 or 1 weightpercent of added acid or acid generator compounds based on total weightof the formulated solvent-based coating composition. As also referred toherein, an added acid is distinct from residual acid that may be presentin a composition, such as residual acid entrapped in a resin remainingfrom the resin synthesis.

If an added acid or acid generator compound are employed, a coatingcomposition suitably comprises a thermal acid generator compound (i.e.compound that generates acid upon thermal treatment), such as an ionicor substantially neutral thermal acid generator, e.g. an ammoniumarenesulfonate salt, for catalyzing or promoting crosslinking duringcuring of an antireflective composition coating layer. Typically one ormore thermal acid generators are present in an antireflectivecomposition in a concentration from about 0.1 to 10 percent by weight ofthe total of the dry components of the composition (all componentsexcept solvent carrier), more preferably about 2 percent by weight ofthe total dry components.

Coating compositions of the invention also may contain one or morephotoacid generator compounds typically in addition to another acidsource such as an acid or thermal acid generator compound. Use of suchphotoacid generator component is not to render the compositionphotoimageable, but rather to enhance resolution of images formed in anovercoated photoresist layer. Thus, a photoacid generator in theunderlying coating composition will not be activated (i.e. photoacidgenerated) until exposure of the overcoated photoresist layer.

Generally preferred photoacid generators for such use in underlyingcompositions of the invention include e.g. onium salts such asdi(4-tert-butylphenyl)iodonium perfluoroctane sulphonate, halogenatednon-ionic photoacid generators such as1,1-bis[p-chlorophenyl]-2,2,2-trichloroethane, and other photoacidgenerators disclosed for use in photoresist compositions.

Formulation of an Underlying Coating Composition

To make a liquid coating composition of the invention, the components ofthe underlying coating composition are dissolved in one or more suitablesolvents such as, for example, one or more oxyisobutyric acid estersparticularly methyl-2-hydroxyisobutyrate as discussed above, ethyllactate or one or more of the glycol ethers such as 2-methoxyethyl ether(diglyme), ethylene glycol monomethyl ether, and propylene glycolmonomethyl ether; solvents that have both ether and hydroxy moietiessuch as methoxy butanol, ethoxy butanol, methoxy propanol, and ethoxypropanol; esters such as methyl cellosolve acetate, ethyl cellosolveacetate, propylene glycol monomethyl ether acetate, dipropylene glycolmonomethyl ether acetate and other solvents such as dibasic esters,propylene carbonate and gamma-butyro lactone. A preferred solvent for anantireflective coating composition of the invention ismethyl-2-hydroxyisobutyrate, optionally blended with anisole. Theconcentration of the dry components in the solvent will depend onseveral factors such as the method of application. In general, thesolids content of an antireflective composition varies from about 0.5 to20 weight percent of the total weight of the coating composition,preferably the solids content varies from about 2 to 10 weight of thecoating composition.

Resins and Organic Solutions/Solvates of Resins

As discussed above, in a further aspect, the invention also includespolymers which comprises repeat units that contain modified imidegroups, such as modified maleimide or glutarimide groups, as disclosedherein.

Suitable resins of the invention that contain imide functionalities aredescribed herein.

In certain preferred aspects, a polyglutarimide is provided where theresin is a substantial hompolymer (e.g. where at least 85, 90, 95, 98 or99 percent of total repeat units are glutarimide units or modifiedglutarimide units), where a portion (e.g. at least 0.5, 1, 5, 10, 20,30, 40, 50, 60, 70, 80, or 90 percent of total glutarimide repeat units)have N-substitution modification, e.g. where the glutarimide nitrogen issubstituted with an ester or acetal group.

In additional preferred aspects, a polymaleimide, which suitably may bea copolymer or other higher order polymer (i.e. the polymer may suitablycomprise repeat units other than maleimide), where a portion (e.g. atleast 0.5, 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, or 90 percent of totalmaleimide repeat units) have N-substitution modification, e.g. where themaleimide nitrogen is substituted with an ester or acetal group.

The invention also include a such polymers that comprise repeat unitsthat contain modified imide groups, wherein the polymer is solvated (atleast significantly in solution at 10 percent total solids composition)at room temperature (24° C.) in one or more organic solvents used toformulate photoresist compositions such as ethyl lactate and/orpropylene glycol methyl ether acetate. Solvation is assessed by nakedeye inspection, i.e. no visible particulate matter from the polymer inthe 10 percent solids solution.

Exemplary Overcoating Composition Layers

As discussed above, a further overlying composition may be used with acoating composition of the invention such as in the manufacture of asemiconductor or other microelectronic device. A wide variety ofcomposition may be overcoated including e.g. a photoresist composition,a hardmask composition, a lift-off layer, a passivation layer, or othercomposition layer.

A variety of photoresist compositions can be employed with coatingcompositions of the invention, including positive-acting andnegative-acting photoacid-generating compositions. Photoresists usedwith underlying compositions of the invention typically comprise a resinbinder and a photoactive component, typically a photoacid generatorcompound. Preferably the photoresist resin binder has functional groupsthat impart alkaline aqueous developability to the imaged resistcomposition.

Particularly preferred photoresists for use with underlying compositionsof the invention are chemically-amplified resists, particularlypositive-acting chemically-amplified resist compositions, where thephotoactivated acid in the resist layer induces a deprotection-typereaction of one or more composition components to thereby providesolubility differentials between exposed and unexposed regions of theresist coating layer. A number of chemically-amplified resistcompositions have been described, e.g., in U.S. Pat. Nos. 4,968,581;4,883,740; 4,810,613; 4,491,628 and 5,492,793, al of which areincorporated herein by reference for their teaching of making and usingchemically amplified positive-acting resists. Coating compositions ofthe invention are particularly suitably used with positivechemically-amplified photoresists that have acetal groups that undergodeblocking in the presence of a photoacid. Such acetal-based resistshave been described in e.g. U.S. Pat. Nos. 5,929,176 and 6,090,526.

The underlying compositions of the invention also may be used with otherpositive resists, including those that contain resin binders thatcomprise polar functional groups such as hydroxyl or carboxylate and theresin binder is used in a resist composition in an amount sufficient torender the resist developable with an aqueous alkaline solution.Generally preferred resist resin binders are phenolic resins includingphenol aldehyde condensates known in the art as novolak resins, homo andcopolymers or alkenyl phenols and homo and copolymers ofN-hydroxyphenyl-maleimides.

Preferred positive-acting photoresists for use with an underlyingcoating composition of the invention contains an imaging-effectiveamount of photoacid generator compounds and one or more resins that areselected from the group of:

1) a phenolic resin that contains acid-labile groups that can provide achemically amplified positive resist particularly suitable for imagingat 248 nm. Particularly preferred resins of this class include: i)polymers that contain polymerized units of a vinyl phenol and an alkylacrylate, where the polymerized alkyl acrylate units can undergo adeblocking reaction in the presence of photoacid. Exemplary alkylacrylates that can undergo a photoacid-induced deblocking reactioninclude e.g. t-butyl acrylate, t-butyl methacrylate, methyladamantylacrylate, methyl adamantyl methacrylate, and other non-cyclic alkyl andalicyclic acrylates that can undergo a photoacid-induced reaction, suchas polymers in U.S. Pat. Nos. 6,042,997 and 5,492,793; ii) polymers thatcontain polymerized units of a vinyl phenol, an optionally substitutedvinyl phenyl (e.g. styrene) that does not contain a hydroxy or carboxyring substituent, and an alkyl acrylate such as those deblocking groupsdescribed with polymers i) above, such as polymers described in U.S.Pat. No. 6,042,997, incorporated herein by reference; and iii) polymersthat contain repeat units that comprise an acetal or ketal moiety thatwill react with photoacid, and optionally aromatic repeat units such asphenyl or phenolic groups; such polymers have been described in U.S.Pat. Nos. 5,929,176 and 6,090,526.

2) a resin that is substantially or completely free of phenyl or otheraromatic groups that can provide a chemically amplified positive resistparticularly suitable for imaging at sub-200 nm wavelengths such as 193nm. Particularly preferred resins of this class include: i) polymersthat contain polymerized units of a non-aromatic cyclic olefin(endocyclic double bond) such as an optionally substituted norbornene,such as polymers described in U.S. Pat. Nos. 5,843,624, and 6,048,664;ii) polymers that contain alkyl acrylate units such as e.g. t-butylacrylate, t-butyl methacrylate, methyladarnantyl acrylate, methyladamantyl methacrylate, and other non-cyclic alkyl and alicyclicacrylates; such polymers have been described in U.S. Pat. No. 6,057,083;European Published Applications EP01008913A1 and EP00930542A1; and U.S.pending patent application Ser. No. 09/143,462, and iii) polymers thatcontain polymerized anhydride units, particularly polymerized maleicanhydride and/or itaconic anhydride units, such as disclosed in EuropeanPublished Application EP01008913A1 and U.S. Pat. No. 6,048,662.

3) a resin that contains repeat units that contain a hetero atom,particularly oxygen and/or sulfur (but other than an anhydride, i.e. theunit does not contain a keto ring atom), and preferable aresubstantially or completely free of any aromatic units. Preferably, theheteroalicyclic unit is fused to the resin backbone, and furtherpreferred is where the resin comprises a fused carbon alicyclic unitsuch as provided by polymerization of a norborene group and/or ananhydride unit such as provided by polymerization of a maleic anhydrideor itaconic anhydride. Such resins are disclosed in PCT/US01/14914.

4) a resin that contains fluorine substitution (fluoropolymer), e.g. asmay be provided by polymerization of tetrafluoroethylene, a fluorinatedaromatic group such as fluoro-styrene compound, and the like. Examplesof such resins are disclosed e.g. in PCT/US99/21912.

Suitable photoacid generators to employ in a positive or negative actingphotoresist overcoated over a coating composition of the inventioninclude imidosulfonates such as compounds of the following formula:

wherein R is camphor, adamantane, alkyl (e.g. C₁₋₁₂ alkyl) andperfluoroalkyl such as perfluoro(C₁₋₁₂alkyl), particularlyperfluorooctanesulfonate, perfluorononanesulfonate and the like. Aspecifically preferred PAG isN-[(perfluorooctanesulfonyl)oxy]-5-norbornene-2,3-dicarboximide.

Sulfonate compounds are also suitable PAGs for resists overcoated acoating composition of the invention, particularly sulfonate salts. Twosuitable agents for 193 nm and 248 nm imaging are the following PAGS 1and 2:

Such sulfonate compounds can be prepared as disclosed in European PatentApplication 96118111.2 (publication number 0783136), which details thesynthesis of above PAG 1.

Also suitable are the above two iodonium compounds complexed with anionsother than the above-depicted camphorsulfonate groups. In particular,preferred anions include those of the formula RSO₃— where R isadamantane, alkyl (e.g. C₁₋₁₂ alkyl) and perfluoroalkyl such asperfluoro (C₁₋₁₂alkyl), particularly perfluorooctanesulfonate,perfluorobutanesulfonate and the like.

Other known PAGS also may be employed in photoresist used withunderlying coating compositions.

A preferred optional additive of photoresists overcoated a coatingcomposition of the invention is an added base, particularlytetrabutylammonium hydroxide (TBAH), or tetrabutylammonium lactate,which can enhance resolution of a developed resist relief image. Forresists imaged at 193 nm, a preferred added base is a hindered aminesuch as diazabicyclo undecene or diazabicyclononene. The added base issuitably used in relatively small amounts, e.g. about 0.03 to 5 percentby weight relative to the total solids.

Preferred negative-acting resist compositions for use with an overcoatedcoating composition of the invention comprise a mixture of materialsthat will cure, crosslink or harden upon exposure to acid, and aphotoacid generator.

Particularly preferred negative-acting resist compositions comprise aresin binder such as a phenolic resin, a crosslinker component and aphotoactive component of the invention. Such compositions and the usethereof have been disclosed in European Patent Applications 0164248 and0232972 and in U.S. Pat. No. 5,128,232 to Thackeray et al. Preferredphenolic resins for use as the resin binder component include novolaksand poly(vinylphenol)s such as those discussed above. Preferredcrosslinkers include amine-based materials, including melamine,glycolurils, benzoguanamine-based materials and urea-based materials.Melamine-formaldehyde resins are generally most preferred. Suchcrosslinkers are commercially available, e.g. the melamine resins soldby Cytec Industries under the trade names Cymel 300, 301 and 303.Glycoluril resins are sold by Cytec Industries under trade names Cymel1170, 1171, 1172, Powderlink 1174, and benzoguanamine resins are soldunder the trade names of Cymel 1123 and 1125.

Suitable photoacid generator compounds of resists used with underlyingcompositions of the invention include the onium salts, such as thosedisclosed in U.S. Pat. Nos. 4,442,197, 4,603,10, and 4,624,912, eachincorporated herein by reference; and non-ionic organic photoactivecompounds such as the halogenated photoactive compounds as in U.S. Pat.No. 5,128,232 to Thackeray et al. and sulfonate photoacid generatorsincluding sulfonated esters and sulfonlyoxy ketones. See J. ofPhotopolymer Science and Technology, 4(3):337-340 (1991), for disclosureof suitable sulfonate PAGS, including benzoin tosylate, t-butylphenylalpha-(p-toluenesulfonyloxy)-acetate and t-butylalpha(p-toluenesulfonyloxy)-acetate. Preferred sulfonate PAGs are alsodisclosed in U.S. Pat. No. 5,344,742 to Sinta et al. The abovecamphorsulfoanate PAGs 1 and 2 are also preferred photoacid generatorsfor resist compositions used with the underlying compositions of theinvention, particularly chemically-amplified resists of the invention.

Photoresists for use with an underlying composition of the inventionalso may contain other materials. For example, other optional additivesinclude actinic and contrast dyes, anti-striation agents, plasticizers,speed enhancers, etc. Such optional additives typically will be presentin minor concentration in a photoresist composition except for fillersand dyes which may be present in relatively large concentrations suchas, e.g., in amounts of from about 5 to 50 percent by weight of thetotal weight of a resist's dry components.

As discussed, other compositions may be applied above a coatingcomposition of the invention. For instance, a hardmask composition maybe applied above a coating composition. Suitable hardmask compositionmay comprise an organic resin with silicon content. Exemplary hard maskcomposition are described in U.S. Pat. No. 7,017,817 to Pavelchek et al.Preferred hardmask compositions may comprise a mixture of distinctresins, wherein the mixture includes at least one resin that has siliconcontent and at least one resin distinct from the Si-resin that haschromophore groups that can effectively absorb radiation employed toexpose an overcoated photoresist layer. By stating that a resin isdistinct from an Si-resin, the differences will include the chemicalcomposition of the resin with respect to the Si-resin and thedifferences will not be limited solely to molecular weight. Forinstance, a distinct resin may not have any Si-content. In a particularpreferred aspect, a hardmask composition may comprise a resin with highSi content which is mixed with an organic resin that comprises exposureradiation-absorbing chromophores. Chromophore groups are typicallyaromatic groups such as optionally substituted phenyl, optionallysubstituted naphthyl or optionally substituted anthracenyl.

Suitable hard mask compositions such as a silicon oxide also may bechemical vapor deposited (CVD) above an underlying coating compositionof the invention.

Suitable lift-off layers are disclosed in U.S. Pat. No. 7,056,824 toMirth. An underlying coating composition of the invention also could beemployed as a lift-off layer. After being disposed on the substrate, thelift-off layer coating composition is heated to remove any solvent (i.e.soft baked) and to provide a lift-off-layer on the substrate. One ormore polymeric coatings, such as a photoresist or antireflective coatingcomposition, are then typically disposed on the lift-off-layer by anyconventional means. Typically, such polymeric coating is disposed on thelift-off-layer by spin coating. The polymeric coating composition isthen heated to remove solvent. When the polymeric composition is anantireflective coating composition, it is next cured (cross-linked)prior to the disposition of any photoresist on the antireflectivecoating. Such curing step may be performed by any suitable means, suchas heating, irradiation or a combination of heating and irradiation. Inone embodiment, one or more layers of a photoresist composition aredisposed on the lift-off-layer. In another embodiment, one or morelayers of an antireflective coating are disposed on the lift-off-layerand then one or more layers of a photoresist are then disposed on theantireflective coating layer(s).

Lithographic Processing of Underlying Coating Compositions that areThermally Deprotectable

In use, a coating composition of the invention is applied as a coatinglayer to a substrate by any of a variety of methods such as spincoating. The coating composition in general is applied on a substratewith a dried layer thickness of between about 0.02 and 0.5 μm,preferably a dried layer thickness of between about 0.04 and 0.20 μm.The substrate is suitably any substrate used in processes involvingphotoresists. For example, the substrate can be silicon, silicon dioxideor aluminum-aluminum oxide microelectronic wafers. Gallium arsenide,silicon carbide, ceramic, quartz or copper substrates may also beemployed. Substrates for liquid crystal display or other flat paneldisplay applications are also suitably employed, for example glasssubstrates, indium tin oxide coated substrates and the like. Substratesfor optical and optical-electronic devices (e.g. waveguides) also can beemployed.

As discussed above, preferably the applied coating layer is thermallytreated before a photoresist composition is applied over theantireflective composition. Cure conditions will vary with thecomponents of the coating composition. Typical thermal treatmentconditions may be suitably from about 150° C. to 250° C. for about 0.5to 5 minutes. Thermal treatment conditions preferably render the coatingcomposition coating layer substantially insoluble or non-mixable withphotoresist solvent, but soluble in alkaline aqueous developer solution.

After such thermal treatment, a further coating composition may beapplied above the coating composition layer.

For example, a photoresist composition may be applied above the surfaceof the top coating composition. As with application of the bottomcoating composition layer(s), the overcoated photoresist can be appliedby any standard means such as by spinning, dipping, meniscus or rollercoating. Following application, the photoresist coating layer istypically dried by heating to remove solvent preferably until the resistlayer is tack free. Optimally, essentially no intermixing of theunderlying composition layer and overcoated photoresist layer shouldoccur.

The resist layer is then imaged with activating radiation through a maskin a conventional manner. The exposure energy is sufficient toeffectively activate the photoactive component of the resist system toproduce a patterned image in the resist coating layer. Typically, theexposure energy ranges from about 3 to 300 mJ/cm² and depending in partupon the exposure tool and the particular resist and resist processingthat is employed. The exposed resist layer may be subjected to apost-exposure bake if desired to create or enhance solubilitydifferences between exposed and unexposed regions of a coating layer.For example, negative acid-hardening photoresists typically requirepost-exposure heating to induce the acid-promoted crosslinking reaction,and many chemically amplified positive-acting resists requirepost-exposure heating to induce an acid-promoted deprotection reaction.Typically post-exposure bake conditions include temperatures of about50° C. or greater, more specifically a temperature in the range of fromabout 50° C. to about 160° C.

The photoresist layer also may be exposed in an immersion lithographysystem, i.e. where the space between the exposure tool (Particularly theprojection lens) and the photoresist coated substrate is occupied by animmersion fluid; such as water or water mixed with one or more additivessuch as cesium sulfate which can provide a fluid of enhanced refractiveindex. Preferably the immersion fluid (e.g., water) has been treated toavoid bubbles, e.g. water can be degassed to avoid nanobubbles.

References herein to “immersion exposing” or other similar termindicates that exposure is conducted with such a fluid layer (e.g. wateror water with additives) interposed between an exposure tool and thecoated photoresist composition layer.

The exposed resist coating layer is then developed, preferably with anaqueous based developer such as an alkali exemplified by tetramethylammonium hydroxide, sodium hydroxide, potassium hydroxide, sodiumcarbonate, sodium bicarbonate, sodium silicate, sodium metasilicate,aqueous ammonia or the like. Alternatively, organic developers can beused. In general, development is in accordance with art recognizedprocedures. Following development, a final bake of an acid-hardeningphotoresist is often employed at temperatures of from about 100° C. toabout 150° C. for several minutes to further cure the developed exposedcoating layer areas.

As discussed above, in preferred systems, development of the photoresistlayer with aqueous alkaline developer also can remove underlying coatingcomposition regions that underlie the developer-removed photoresistareas.

The developed substrate may then be selectively processed on thosesubstrate areas bared of photoresist, for example, chemically etching orplating substrate areas bared of photoresist in accordance withprocedures well known in the art. Suitable etchants include ahydrofluoric acid etching solution and a plasma gas etch such as anoxygen plasma etch.

The following non-limiting examples are illustrative of the invention.

Example 1 Synthesis of Modified Polyglutarimide

To 15.3 g polyglutamide (Mw of 19,096 with a polydispersity of 1.7 and apercent nitrogen content of about 9%) dissolved in 155 g of N,N-dimethylformamide was added with stirring anhydrous potassium carbonate (9.0 g).The mixture was stirred at 21° C. for 30 minutes. t-Butyl bromoacetate(20.0 g) was slowly added to the mixture followed by heating at 75° for18 hours. After cooling the salts were removed by filtration and washedwith a small portions of N,N-dimethylformamide. The combined filtratewas slowly precipitated into 1.0 L of de-mineralized water acidifiedwith 50 mL of 0.1N hydrochloric acid. The precipitated product wascollected on a filter and washed with about 200 mL of di-mineralizedwater. After a partial drying on the filter the polymer was slurried intwo 200 mL portions of methanol. The product was partially dried on thefilter and further dried at 50° C. under vacuum to give about 19.8 g ofmodified polymer. GPC analysis revealed that the obtained polymer had aweight average molecular weight (Mw) of about 26 k and a polydispersity(Mw/Mn) of 1.61.

Example 2

To 15.3 g polyglutamide (Mw of 19,096 with a polydispersity of 1.7 and apercent nitrogen content of about 9%) dissolved in 155 g of N,N-dimethylformamide is added with stirring triethylamine (0.05 g). The mixture wasstirred at 21° C. for 30 minutes. Di-tert-butyl dicarbonate (22.0 g) wasslowly added to the mixture at 25° and stirred for 18 hours. Thesolution was slowly precipitated into 1.0 L of de-mineralized water. Theprecipitated product was collected on a filter and washed with about 200mL of di-mineralized water. After a partial drying on the filter thepolymer was slurried in two 200 mL portions of methanol. The product waspartially dried on the filter and further dried at 50° C. under vacuumto give about 18.4 g of modified polymer.

Example 3

To 15.3 g polyglutamide (Mw of 19,096 with a polydispersity of 1.7 and apercent nitrogen content of about 9%) dissolved in 155 g of N,N-dimethylformamide was added with stirring anhydrous potassium carbonate (9.0 g).The mixture was stirred at 21° C. for 30 minutes. Benzylbromide (3.4 g)was slowly added to the mixture followed by stirring for 4 hours at 21°C. t-Butyl bromoacetate (20.0 g) was slowly added to the mixturefollowed by heating at 75° for 18 hours. After cooling the salts wereremoved by filtration and washed with a small portions ofN,N-dimethylformamide. The combined filtrate was slowly precipitatedinto 1.0 L of de-mineralized water acidified with 50 mL of 0.1Nhydrochloric acid. The precipitated product was collected on a filterand washed with about 200 mL of di-mineralized water. After a partialdrying on the filter the polymer was slurried in two 200 mL portions ofmethanol. The product was partially dried on the filter and furtherdried at 50° C. under vacuum to give about 20.0 g of modified polymer.

Example 4

A solution of the polyglatarimide polyglutamide (Mw of 19,096 with apolydispersity of 1.7 and a percent nitrogen content of about 9%)dissolved in N,N-dimethyl formamide is reacted with di-tert-butyldicarbonate in the presence of triethylamine and dimethylaminopyridineto give the tert-butyl carbamates derivative shown in Scheme 2 above.

Examples 5-24

Additional samples are prepared using the procedures identified inExample 1 with the substituents shown in Table 1 below. In Table 1below, the “R” substituent replaces as appropriate the alkyl(tert-butyl) substituent of the modified imide polymer of Example 1above. Those differing R substituents can be provided by use ofcorresponding bromoacetate reagents as set forth in Example 1 above.

TABLE 1 Substituent Example R 5 iso butyl 6 iso propyl 7 ethyl 8 methyl9 tert. amyl 10 1-ethyl cyclopentyl 11 isobornyl 12 phenyl 13 benzyl 141-methylbenzyl 15 1,1 dimethyl benzyl 16 2-phenylethyl 17 1-adamantyl 182-methylenefuranyl 19 9-methylenefluorenene 20 2-napthylene 219-methyleneanthracene 22 1-diamantane 23 1-cyclohexyl 24 1-cyclopentyl

Examples 25-45

Polymers derivatives are also prepared containing alkyl, alkyl ester andcarbamate derivatives within the same polymer chain. Table 2 providesexamples of some of the derivatives prepared. In Table 2, listed are (1)the percent alkyl ester units percent in the polymer of the specifiedExample (based on total polymer units), (2) the type of alkyl ester thatis present as a modified imide group in the percent amount specified inthe preceding column entry, (3) the percent carbamate units percent inthe polymer of the specified Example (based on total polymer units), (2)the type of carbamate that is present as a modified imide group in thepercent amount specified in the preceding column entry,

TABLE 2 Percent alkyl Type alkyl Percent Example ester ester carbamateType carbamate 25 50 tert. butyl 50 phenyl 26 50 tert. butyl 50 benzyl27 50 tert. butyl 50 1-methylbenzyl 28 50 tert. butyl 50 1,1 dimethylbenzyl 29 50 tert. butyl 50 2-phenylethyl 30 75 tert. butyl 252-napthylene 31 75 tert. butyl 25 9-methyleneanthracene 32 75 tert.butyl 25 phenyl 33 75 tert. butyl 25 benzyl 34 75 tert. butyl 251-methylbenzyl 35 75 tert. butyl 25 1,1 dimethyl benzyl 36 75 tert.butyl 25 2-phenylethyl 37 75 tert. butyl 25 2-napthylene 38 75 tert.butyl 25 9-methyleneanthracene 39 25 tert. butyl 75 phenyl 40 25 tert.butyl 75 benzyl 41 25 tert. butyl 75 1-methylbenzyl 42 25 tert. butyl 751,1 dimethyl benzyl 43 25 tert. Butyl 75 2-phenylethyl 44 25 tert. Butyl75 2-napthylene 45 25 tert. Butyl 75 9-methyleneanthracene

Example 46 Synthesis of Styrene/Maleimide Copolymer

To a 250 mL three necked round bottom flask equipped with silicon oiltemperature controlled bath, condenser, magnetic stirrer, thermometerand nitrogen blanket was added styrene (4.85 g), maleimide (5.15 g) andtetrahydrofuran (22.4 g). The bath temperature was set to 65° C. tobring the flask to reflux. While heating, a 10% solution of Vazo 67(0.95 g) in tetrahydrofuran was prepared. When the monomer solution wasat reflux, 80% solution of the initiator was charged to the flask. Thepolymer solution was held for 1 hour 30 minutes at reflux, this was thenfollowed by another addition of initiator (20%) solution and thereaction held for 18 hours at this temperature. The reaction solutionwas cooled and the product precipitated into hexanes. Upon drying 10 gof product was recovered. GPC analysis revealed that the obtainedpolymer had a weight average molecular weight (Mw) of about 70,000 and apolydispersity (Mw/Mn) of 3.3.

Example 47 Alkylation of Styrene/Maleimide Copolymer and its ThermalDecompositon

In a 250 mL three necked round bottom flask equipped with a magneticstirrer and over head condenser, 2.5 g of Styrene/Maleimide copolymer(0.025 Moles) were dissolved in tetrahydrofuran and stirred at roomtemperature for ten minutes. 2.65 g (0.019 Moles) of K₂CO₃ was chargedinto the reaction mixture and further stirred for 10 minutes. 3.7 g(0.019 Moles) of t-Butyl bromoacetate was then slowly added to thereaction mixture over a period of 15 minutes while stirring. The mixturewas then placed in an oil bath set at 75° C. and stirred at thistemperature for 23 hours. The reaction was quenched by pouring themixture slowly into 500 mL of 0.1% HCl solution and stirred for 10hours. The precipitate was filtered and placed in a flask and coveredwith 500 mL of 0.1% HCl solution spiked with 5% methanol so as todissolve the unreacted t-Butyl bromoacetate. This solution was stirredover 12 hours, the precipitate filtered in a Buchner, and rinsed withlots of water. The precipitate was then dried overnight at 50° C. undervacuum.

Examples 48 Through 57 Underlying Compositions

In these Examples 48 through 57, each composition was prepared bycharging the indicated components into a clean bottle without regard toorder of addition. The samples were shaken or placed on rollers untilcompletely dissolved. Each sample was then passed through a 0.2 μm PTFEmembrane filter into a clean bottle.

Results as set forth in Table 1 below demonstrate polymer insolubilityto a typical resist solvent and to a developer after a thermaltreatment.

Polymers of Example 1 and 3 were each dissolved in ethyl lactate. To thesolution of Example 48 to 52 about 1 weight percent of dodecylbenzenesulfonic acid with amine was added to form 10 weight percent solutions.To the solution of Example 53 to 57 about 3 weight percent ofdodecylbenzene sulfonic acid with amine was added. The solutions werespin coated on 4 inch silicon wafer and baked for one minute at theindicated temperature. One wafer of each set was covered with a puddleof the indicated solvent for 60 seconds and then spun dry. The developerwas 0.26N tetramethylammonium hydroxide, TMAH, solution. Film thickness(FT) was measured after the bake and after the solvent or developerexposure using a NANOSPEC 300 instrument. In Table 3 below, the solventis Propylene glycol monomethyl ether acetate is referred to as PGMEA andmethyl hydroxy isobutyrate is referred to as HBM.

TABLE 3 FT After 225° C./60 sec FT After FT Loss Example No. Å Solvent60 sec. Soak Å Å 48 2931 Ethyl Lactate 2701 230 49 2870 PGMEA 2849 21 502855 Cyclohexanone 2850 5 51 2872 HBM 2865 7 52 2880 CD26 0.0 2880 533151 Ethyl Lactate 2652 499 54 3247 PGMEA 3196 51 55 3132 HBM 3137 +5 563134 2-Heptanone 3137 +3 57 3100 CD26 0 3100

Example 58 Planarization

Coating composition of Example 4 was spin coated on substrate, baked at225° C./60 seconds. Film thickness is 300 nm. Substrate topography is150 nm via, 150 nm pitch, 400 nm deep. Isolated trench is 5000 nm.Scanning electron micrographs of substrate overcoated with this coatingcomposition are shown in FIGS. 1A, 1B and 1C.

Examples 59-61 Reactive Etch

Polymer solutions of Example 1 were spin coated onto 8 inch siliconwafers to give about 3000 Å thick films. The wafers were than subjectedto several different etch conditions and etch rates measured. Resultsare set forth in the following Table 4.

TABLE 4 Etch Rate Example No. Plasma Composition (nm/min.) Example 59O₂/CO 1229 Example 60 CF₄/O₂/Ar 175 Example 61 H₂/N₂ >1600

Example 62 Lithographic Processing

This example shows use of an underlying coating composition of theinvention as an underlayer/anti reflective layer to a 193 nm resist.

Process Conditions

1) Underlayer: 215 nm coating layer of Example 5 is thermally treated at200° C./60 seconds on a vacuum hotplate;

2) Photoresist: 260 nm coating layer of an acrylate-based 193 nmphotoresist soft-baked at 120° C./60 seconds on a vacuum hotplate;

3) Exposure: the applied photoresist layer is exposed to patterned 193nm radiation;

4) Post-Exposure Bake: 120° C./60 seconds;

5) Development: the latent image is developed with 0.26N aqueousalkaline developer to provide a photoresist relief image.

1. A method of preparing an electronic device, comprising: applying anorganic composition on a substrate, the organic composition comprise oneor more resins with modified imide groups; and applying a furthercomposition above the organic composition.
 2. The method of claim 1further comprising thermally treating the organic composition layerprior to applying the further composition.
 3. The method of claim 2wherein thermal treatment does not significantly increase molecularweight of the resin.
 4. The method of claim 1 wherein the imide groupsare substituted with ester groups or acetal groups.
 5. The method ofclaim 1 wherein the one or more resins comprise glutarimide and/ormaleimide groups and/or the organic composition comprises one or moreresins with one or more chromophore groups.
 6. The method of claim 1wherein the further composition layer is a photoresist composition, alift-off composition, a passivation composition or a hardmaskcomposition.
 7. A coated substrate comprising: an organic composition ona substrate, the organic composition comprise one or more resins withmodified imide groups; and a further composition layer above the organiccomposition.
 8. The method of claim 7 wherein the one or more resinscomprise glutarimide and/or maleimide groups and/or one or morechromophore groups.
 9. An underlying coating composition comprising oneor more resins comprising one or more modified imide groups.
 10. Anorganic solvent solution comprising (1) one or more organic solvents and(2) a composition of claim 9.